Research On Underwater Explosion Resistance Of Multi-layer Gradient Lattice Sandwich Structure

The lightweight sandwich structure characterized by greater specific rigidity and specific strength has excellent cushioning and energy absorption capabilities under the impact of underwater explosions.The energy absorption of the sandwich structure can be fully exerted under the underwater explosion impact when a gradient design scheme was adopted in the multi-layer core due to the deformation coupling effect of each layer of the sandwich structure.The underwater explosion resistance of layered density gradient pyramid sandwich panels is analyzed by combining experimental method and numerical simulation.Firstly,the multi-layer stainless steel pyramid lattice sandwich specimens are designed and fabricated,and the density gradient between core layers is realized by changing the crosssectional dimensions of truss bar.The underwater explosion test was carried out by setting up an underwater explosion experimental tank.The impact wave was generated by the near-water surface explosion of 200 g of TNT explosive.The stress of the bars supporting the sandwich structure was tested by a dynamic testing device.The transmitted loads and the deformation modes of multi-layer homogeneous lattice sandwich structure and multi-layer density gradient lattice sandwich structure were,comparatively,analyzed under underwater explosion impact.Second,the finite element analyzing software ABAQUS was used to analyze the load transmission of the multi-layer lattice sandwich structure subjected to the underwater explosion loading.The transmitted load obtained in numerical simulation was compared with the experimental results.The energy absorption and the core deformation performance of the multilayer sandwich structure were systematically studied.The effect of the configuration on the underwater explosion resistance was discussed.Finally,ABAQUS software was used to numerically analyze the underwater explosion resistance of the clamped lattice sandwich structure.The non-reflective boundary conditions were used to simulate the underwater explosion impact in infinite water field.The peak deflection of the back face-sheet,the supporting force at the edge of the structure and the energy absorption were taken as the evaluation indexes of the anti-explosive performance.The effect of the density gradient ratio of the gradient lattice sandwich structure,the thickness ratio of the front/back face-sheet and the explosive quantity on the underwater explosion resistance of the structure was discussed.The corresponding conclusions obtained in this paper can provide theoretical reference to the design of lightweight structure and engineering application.